<!DOCTYPE html>
<link rel="author" title="David Shin" href="dshin@mozilla.com">
<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1879731">
<style>
table {
  border-collapse: collapse;
}

.group {
  border-left: 1px solid black;
  border-right: 3px solid black;
}
</style>
<table>
  <tbody id="table">
    <tr><td class="group">X</td></tr>
    <tr><td>X</td></tr>
    <tr><td>X</td></tr>
  </tbody>
</table>
